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What is TTTS? 

What is Twin to Twin Transfusion Syndrome (TTTS)

Twin to Twin Transfusion Syndrome (TTTS) is a rare but life-threatening condition that affects 10 to 15 percent of identical twins that share a placenta (monochorionic twins). TTTS can also occur in triplet or higher order pregnancies with monochorionic twins. If untreated, 90 percent of babies are likely to die. Even with treatment, 50 percent of surviving babies are likely to be disabled or have a long term condition.

The blood vessels within and on the surface of the shared placenta connecting both twins should allow blood to flow evenly between the babies so that each baby receives the same amount. However, in TTTS, part of the blood flow is diverted from one ‘donor’ twin to the other ‘recipient’ twin in what is effectively a blood transfusion (hence the name).

A lack of blood supply can affect the donor twin’s growth so they are smaller than average. The recipient twin is usually larger and has a higher blood volume, which can strain their heart as it works harder to cope with the extra blood supply.

To compensate for the excess blood, the recipient twin often produces a large amount of fluid. In contrast, the smaller donor twin can become stuck against the uterus wall with little surrounding fluid.

Find more information about TTTS, including Tamba's TTTS Guide here. 

Who does TTTS affect?

TTTS only affects identical twins who share a placenta. TTTS can also occur in triplet or higher order pregnancies with monochorionic twins. They are referred to as monochorionic twins because they share an outer membrane (chorion) – the technical term is MCDA and MCMA twins.

What are the treatment options?

If the TTTS is mild (Stage I), no treatment may be required and it is possible that the condition will remain stable or improve. The pregnancy will be closely monitored and if TTTS becomes more severe, the doctors may recommend intervention. The choice of treatment will depend upon the stage of TTTS and how many weeks pregnant the mother is.  

There are three possible treatment options for TTTS:

  • Amnioreduction  - involves draining excess amniotic fluid from around the larger recipient twin.

  • Laser ablation – this therapy involves finding every blood vessel connecting the twins and closing them to prevent the flow of blood from one baby to the other and the possible risk of transfusion.
  • Selective feticide - In a few cases, the only way to prevent the loss of both twins is to close off the blood flow to the sick baby’s cord sadly meaning the baby will die in the womb.

To find out more information on TTTS, visit our website or download our TTTS guide.  

What is the TTTS Appeal for?

Currently there is too little research conducted looking at the most effective treatments for TTTS in the short or longer term.  There is no comprehensive outcome data collected and published in the UK so doctors cannot compare what is working best and why.  There are also no longer term follow ups to understand the longer term consequences of individual treatments. That is why we have partnered with St George’s hospital and other fetal medicine centres throughout the UK to set up a UK-wide registry of all TTTS pregnancies, their treatments and outcomes.  A comprehensive set of data can then be collected and analysed. Dr. Asma Khalil, from St Georges’s hospital, who is leading this project, said, “This will help to build a true picture of TTTS cases in the UK, the survival rates and outcomes.  Crucially, a national UK Registry will provide a tool to assist the improvement of clinical skills and practice and therefore help to provide better patient care at a local, regional and national level.  It will also establish a platform to allow long term follow up of TTTS survivors at a national level showing the longer term neurodevelopment outcomes.  The data will also be invaluable for future ongoing research into TTTS, for example, the longer term consequences of individual treatments.  Eventually we would also try to replicate this model internationally.” 

We are delighted to announce that with all the fantastic support we have received we have managed to raise our £30,000 initial target to get the TTTS Registry up and running.  The TTTS Registry will be going live in October 2015 and any niggles worked on through the rest of the year. The TTTS registry will be a UK first and is the most practical way of driving improvements in the next few years and longer term.  

We are keeping the TTTS Appeal as an ongoing appeal because there will be continuous running costs associated with the registry and we need to appoint a research midwife to liaise with the hospital units to ensure the data is collected and entered correctly etc. We will also be extending the registry to cover other TTTS complications such as TAPS and TRAPS. So your continued fundraising is very much needed and greatly appreciated!

In the third phase we will be looking to fund follow up studies as well. 



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